Overstrand, a Generation Restoration pilot city, created an integrated catchment-to-coast restoration plan for the Onrus wetland and estuary. The project involved baseline analyses and regulatory groundwork needed to enable future rehabilitation work, and engaged local communities, landowners, and NGOs through stakeholder workshops and awareness activities to build long-term support.
About the city
Overstrand is a municipality in South Africa’s Western Cape, located in the southwest of the country. Its population is approximately 133,000 residents spread across almost 60,000 households, with the principal towns of Hermanus, Gansbaai and Kleinmond. Overstrand is located on the coast of the Atlantic Ocean, and it has a Mediterranean climate with warm, dry summers and cold, wet winters. Overstrand’s economy and the livelihoods of its population are heavily reliant on tourism, agriculture, fishing, forestry, and manufacturing.
Local challenges
Overstrand is increasingly impacted by climate change, particularly through more frequent heatwaves and storms affecting the area. Furthermore, changing rainfall patterns and more frequent droughts pose numerous threats, including drying out of wetlands, increased risk of fire, and reduced water supplies for agricultural, industrial, and domestic needs. At the same time, Overstrand’s coastal location makes it susceptible to sea level rise, which threatens infrastructure, residential areas, and terrestrial ecosystems, including farming areas, with flooding and saltwater intrusion. Growing urban sprawl in the area also leads to biodiversity loss, particularly due to invasive species, pollution, and habitat destruction. Local populations, freshwater ecosystems, and marine areas are negatively impacted by both plastic pollution and water pollution from agricultural runoff and city wastewater discharges. Economic inequality and poverty exacerbate these challenges, particularly among vulnerable populations, who often live in informal settlements.
The pilot project specifically addresses challenges associated with the Onrus catchment system and the Onrus wetland, a peat wetland located close to the town of Hermanus that is important for biodiversity and flood control. Although it was historically hardy and erosion-resistant, various disturbances have eroded the Onrus wetland over time, including drying of the wetland following the construction of a dam upstream, proliferation of invasive vegetation in the area, and a fire event in 2019 that degraded its underground structure. The wetland was then severely damaged by flooding in 2023 and 2024, which exacerbated its erosion, resulting in the loss of approximately 75% of this important ecosystem.
Action through Generation Restoration
The Generation Restoration pilot project in Overstrand aimed to rehabilitate the Onrus wetland and set up conditions for broader restoration in the Onrus catchment area, to safeguard water resources, prevent land degradation, preserve biodiversity, and mitigate the effects of climate change.
The project began with an information session with local interested stakeholders, including local community members, landowners, NGOs, and government representatives. The session included an overview of the pilot project objectives and upcoming technical work, including baseline studies, hydrological and invasive-species assessments, and the preparation of the Maintenance Management Plan.
Preliminary technical work included detailed baseline assessments of the Onrus wetland, primarily using existing datasets and remote sensing data, to understand the wetland’s current status, drivers of degradation, and determine a plan for restoration/rehabilitation. Baseline surveys included a review of the extent and intensity of invasive species proliferation in the wetland, producing a full GIS dataset of invasive species and areas of land transformation to guide prioritization and budget planning. A hydrology assessment quantified historic changes in surface and groundwater flow across the Onrus catchment and identified key drivers of reduced streamflow and wetland degradation. From this baseline data, the project produced a design report outlining the proposed restoration methods that would be implemented pending further funding. These include constructing six gabion weirs (a rock-filled wire basket structure that slows water flow and prevents erosion) from upstream to downstream to slow water flow and rebuild the wetland’s structure, and utilizing excavated peat and rescued vegetation to fill and reshape eroded gullies, with gentle slopes suitable for replanting indigenous wetland vegetation.
Following the design phase, a detailed ecological health assessment of the Onrus Estuary was undertaken to quantify post-flood degradation and guide the final Estuary Maintenance Management Plan. This study assessed hydrology and hydrodynamics, water quality, habitat status, and biodiversity, confirming that the estuary had become a critically impaired ecosystem requiring immediate intervention. The results informed the preparation of the Maintenance Management Plan for the estuary and lower Onrus River, an operational framework for managing, restoring, and maintaining the Onrus estuary. The proposed restoration interventions included sediment dredging, dewatering, and mouth management to restore hydrodynamic function. Findings were then presented in another meeting with stakeholders to garner feedback on project design and prepare for implementation, pending available resources. Together, the wetland rehabilitation design and the estuary Maintenance Management Plan form two complementary restoration activities to be undertaken “from catchment to coast.”
Additional project activities included developing a proposal for a funding model and potential funding sources to finance the proposed restoration work, based on carbon and biodiversity credit financing, which directly aligns with global trends in climate finance and ecosystem service markets. The project team also developed a document outlining the necessary steps to implement an effective restoration plan in other municipalities, ensuring alignment with legislative and policy frameworks. Public outreach through communications campaigns, awareness materials, and community meetings further strengthened stakeholder engagement and long-term support for restoration efforts.
Main outcomes
The project successfully laid the groundwork for broader implementation in the Onrus catchment and wetland. The project completed a full suite of baseline studies, design reports, and regulatory plans, providing Overstrand Municipality with an actionable roadmap for restoring the Onrus system, including the estuary and wetland. Together, the wetland rehabilitation design and estuary Maintenance Management Plan established a clear implementation framework for restoring hydrological balance, rebuilding degraded habitats, and improving ecosystem connectivity.
The project strengthened institutional collaboration and visibility, including the establishment of a steering committee group uniting local government, NGOs, and national agencies in a shared vision for restoration. The project also enabled the development of key documents which allowed the Municipality to unlock more funding from different sources to continue and scale-up the project and restoration work beyond the pilot’s duration. The Municipality also developed a guiding document for other municipalities in South Africa to carry out similar work.
Through stakeholder workshops, awareness campaigns, and international presentations, the project built local ownership and global visibility for catchment restoration and rehabilitation. A replication guideline and innovative blended finance model were developed to enable other municipalities to adopt similar restoration approaches, scaling the impact of the Generation Restoration initiative beyond Overstrand.